DUBAI/LONDON (Reuters) – Iran has executed a British-Iranian national who once served as its deputy defence minister, its judiciary said, defying calls from London and Washington for his release after he was handed the death sentence on charges of spying for Britain. Britain, which had declared the case against Alireza Akbari politically motivated, condemned the execution, with Prime Minister Rishi Sunak calling it “a callous and cowardly act carried out by a barbaric regime”. Akbari, 61, was arrested in 2019. The Iranian judiciary’s Mizan news agency reported the execution without saying when…